Author Topic: Steve Ward's DRSSTC Interrupter shuts down when adjusting pulse width  (Read 145 times)

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Offline Verliebt_in_München17Topic starter

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Don't know if this is the right place to come to, i suspect it might be about damaged **equipment** but here I am

So early today I've built this DRSSTC Interrupter for my upcoming Tesla coil project and I've ran into a little trouble, the circuit was operating fine the first time I hooked it up, everything was working normally so i hooked up a small 5mm LED with a 330 Ohm resistor to pin 3 of the rightmost 555 timerwhich is the output and is also responsible for adjusting the pulse width with a 5K potentiometer, up until not even 5 mins, mind that the circuit ran for for 5 whole minutes with no problems, the output of the interrupter started spazzing out uncontrollably (which is most likely a curse since that happens with any circuit that i build), i double checked my wiring to no avail, now hooked up the circuit again where everything is working semi-fine again EXCEPT the 555 timer IC which is responsible for controlling the pulse width is somehow not fine, adjusting the pot even a tiny bit causes the interrupter to shut down and seize working and noticably heats up THAT single 555 timer,

Any help on clarifying me on how I should troubleshoot this circuit would be gladly appreciated,
I will provide my sloppy wiring if anyone specifically wants to see that

 :-BROKE :palm:
« Last Edit: June 08, 2024, 11:34:38 pm by Verliebt_in_München17 »

Online fzabkar

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Pin #7 is connected internally to a "low impedance discharge path". A transistor inside the IC discharges the external capacitor at the end of the cycle. If R4 is at max travel so that pin #7 is directly connected to Vcc, then this transistor will be trying to short the supply rail to ground.

IMO there should an additional resistor between pin #7 and the bottom end of R4.
« Last Edit: June 09, 2024, 12:20:08 am by fzabkar »

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